| 摘要 |
Covert security coating is provided to enable a security device to have a dielectric layer forming a Fabry Perot cavity or have a dielectric stack of dielectric layers so that a multilayer thin film filter can function as a covert color coding system useful as the security device. A multilayer thin film filter has an organic dielectric layer(104) therein. The organic dielectric layer(104) performs spanning of plural regions of the filter, and is embossed to define the plural regions of different uniform thicknesses, wherein some adjacent regions of the dielectric layer(104) have a different uniform thickness, and wherein the size of one of the embossed adjacent regions is such that a color of the one region is uniform and cannot be seen by human eyes as a color different from the uniform color of an adjacent region thereto, and wherein the color within a region can be seen with magnification of at least 10:1 or more. |
